Safety device for projectiles



Jan. 19, 1954 E. w. BRANDT SAFETY DEVICE FOR PROJECTILES Fi led Sept. 25 1950 4 1 Liv/Ill!!! 2E!! ml l hl lllll lll m E W. BRA ND 7' INVENTOR.

ATTORN EYS.

Patented Jan. 19, 1954 2,666,390 SAFETY DEVICE FOR PROJECTILES Edgar William Brandt, Geneva, Switzerland, assignor to Anstalt fiir die Entwicklung von Erfindungen und gewerblichen Anwendungen Energa, Vaduz, Liechtenstein, a corporation of Liechtenstein I Application September 25, 1950, Serial No. 186,556

Claims priority, application Switzerland September 26, 1949 This invention relates to new and useful improvements in a safety device for projectiles.

Projectiles are already known which are provided with devices ensuring complete safety both during transportation and handling and on the firing of the shot, that is to say in the barrel of the gun and over a certain distance in front of the mouth of the barrel.

Such devices are often complicated and their operation is controlled by inertia acting on the projectile or else by a clockwork movement.

In this connection mechanisms have been previously proposed which act under the recoil effect of an inertia block on the firing of the shot and as a result of the positive acceleration acquired by the projectile; said mechanisms comprising members connected together by a groove and a member sliding in said groove and liberating with a time lag an obturator intended to prevent premature transmission of fire between a primer and a detonator. The obturator had the form of a hood capping a fire transmission passage, which hood was ejected at the time of arming into a cavity provided for the purpose.

The ejectable obturator occupied, after the arming of the device, a certain space which is not always available, and in addition there was the risk that it might take up its position near the primer or on the path of the jet of the fire thus impeding the transmission of the latter.

The present invention aims at obviating the foregoing disadvantages and provides a safety and fire transmission device provided with a and a detonator spaced from said fuse, comprising a body integral with said projectile, a rota" tionally movable obturator member, a second member taking the place of an inertia block and moved axially under the effect of the positive acceleration of the projectile against an elastic means, one of said members having a groove of which at least part is sinuous and in which the other member carries a sliding element engaged in the groove.

With the foregoing and other objects in view the present invention is characterized in that the obturator member is perforated by a longitudinal passage at least part of which is eccentric, said part being adapted, by rotation of the obturator member, to coincide on arming with one end of a second fixed passage traversing the case of the body of the device, the other end of this latter passage having its outlet near a detonator.

The primary object of this invention resides in the fact that the safety device constitutes a 4 Claims. (Cl. 10278) mechanism entirely independent of the fuse of the projectile. Said fuse may be of any type for use on different sorts of projectiles (rifle grenade with a hollow charge, bazooka bomb, trench mortar shell or other ammunition), in combination with the safety and fire transmission devices as claimed hereafter.

For example, said safety device may be introduced in a rifle grenade of the type described in the patent granted October 14, 1952, No. 2,613,685 on the invention of W. Brandt, between the head fuse and a rear detonator, at the apex of the hood lining the hollow charge.

The technical advantage resulting from this construction is due to the simplicity of its mechanism, consisting in forming an opening for the transmission of fire after the style of a cock casing, the rotation of the obturator being controlled by the recoil of an inertia member associated with said obturator by means of a groove and an element sliding in said groove.

More particularly the invention contemplates a safety and arming device for self-propelled projectiles, the positive acceleration of which continues over a substantial portion of its trajectory. In that case the groove preferably comprises a first sinuous part, which effects the retardation of the arming, a second helicoidal part maintaining continuity of the angular movement of the obturator, and finally a third blind part in which the sliding element is locked as soon as the positive acceleration ceases.

As a result of this construction, after the arm" ing of the device, irrespective of the movement of the projectile on its trajectory and the varia tion of its speed, none of the forces acting are able tomodify the position of the obturator and thereby in any way to obstruct the transmission of fire.

In accordance with the invention, the obturator member is compelled to move only angularly, any axial displacement thereof being prevented by a retaining element.

By virtue of this construction, which does not contain any part issuing from the housing limited by the casing of the safety device, the size of the latter is reduced to the minimum.

In addition, according to a further feature of the invention, the slide controlling the angular movement of the obturator is itself guided axially through a longitudinal opening cut into the body of the safety device, so that the translation of the inertia piece from front to rear necessarily entails rotation of the obturator to the right or to the left, depending on the direction at the 3 given instant of the part of the groove in which ;he sliding element is located.

According to a still further embodiment of ;he invention, the casing of the aforedescribed device, which is obturated at its base by a plug, also encloses a detonator, thus constituting an easily removable assembly. As a result, the pro iectiles may be easily disarmed by the removal )f the detonator alone or by the removal of the whole device.

In order to enable the invention to be more readily understood, reference is made to the ac- :ompanying drawings which illustrate diagramnatically and by Way 'of example, one embodiment thereof and in which:

Fig. 1 is an axial section of the safety device oef ore firing;

Fig. 2 illustrates the plane development of a part of the safety device;

Figs. 3 and 4 are cross-sections along the lines [IL-III and IV IV respectively of Fig. 1;

'Fig'. 5 isan axial section' similar to that of Fig. l, but showing the safety device armed;

Fig. 6 shows a development similar to that of Fig. 2;

Figs. '7 and 8 are axial sections along the lines VIIVII and VIII-V1II respectively of Fig. 5.

In all the figures, like parts are denoted by like reference characters.

Reference numeral l denotes the body of the safety device in which is housed the obturator member 2, which can move only by rotation around the axis .ry of said device, the keeper ring 3 retaining the member 2 in the body I. The latter is crimped at 4 into the casing 5 the lower part 50. of which comprises a sleeve 6 containing the detonator I which is covered, at its top part, by a perforated cap 8, the aperture 9 of which is masked by a wad IE3, while a plug ll retains the sleeve 6 in the casing 5a.

In the embodiment described; the obturator member 2 has a longitudinal passage l2, the lower part it of which is eccentric in relation to the axis xy of the device. A second passage L4 passing through the base of the body I has a slightly oblique direction.

The passages 43 and M are disposed in such manner that their adjacent ends are remote from one another when the device is in the safety position.

An annular inertia member I5 occupies the coaxial housing It provided between the casing 5 and the body i, and surrounds the latter; it can move axially in said housing against a spring H. In the position of rest (Fig. l) a sliding element 3 held by the inertia piece bears against the upper edge of the longitudinal aperture (I9 provided through the body I, and prevents saidim ertia piece from leaving its housing. The aperture l moreover, guides the inertia member l5 along the axis of the safety device and thus precludes any rotation thereof. The end of the sliding element I8 slides, during the movement of translation of the inertia piece IS, in a groove 2| cut in the outer face of the obturator 2, so that said inertia member controls the angular displacement of said obturator according to a movement defined by the path assumed by the groove 2|. A rotation of the obturator 2 through an angle of 180 brings said ends in a position of 00- incidence in which the transmission of fire to the detonator l is possible.

The groove 21', the development of which is shown in Figs. 2 and 6, comprises three distinct parts, namely a first part 2 la which is ofundulatthe effect of the positive acceleration of the projectile, the inertia member i 5 recoils by inertia in its housing [6, against the spring ll. Said inertia member is guided, in its translatory movement by the sliding element [S which passes through the rectilinear aperture IQ of the body I.

Since the end 20 of the slide is compelled to pass through the groove 21 provided in the obturator 2, the latter starts a reciprocating movement around the middle position which it occupies in Fig. 1, this movement taking place While the end 2!! follows the part Zia of the groove 2 i.

This first phase of the movement ensures safety on firing, or muzzle safety, of the projectile, which muzzle safety is determined during the trajectory by the number of sinuosities of the groove 24, the inertia of the inertia piece l5, and the speed of the projectile.

The part Zib of the groove passed through by the end 253 of the slide finally causes the obturator 2 to perform a rotation around an angle of in relation to its initial position (Fig. 2), so that the eccentric portion of the passage [3 coincides with the end of the fixed passage It. From that moment therefore transmission of fire can take place freely between a primer situated at the head of the projectile (not shown) and the detonator 1, according to the path l2l3-l4--S -1 (Fig. 5). When the positive acceleration of the projectile has ceased, the end of the sliding element is held in the blind portion 2E0 of the groove, and thereupon, irrespective of the movement of the projectile, whether accelerated or retarded, the safety device remains armed until the functioning of the fuse which transmits the fire to the detonator l.

It should be noted that the groove 2!, as illustrated has been designed for a device ensuring the safety of a self-propelled projectile, that is to say one the positive acceleration of which takes place over a substantial part of the trajectory. It is obvious that those skilled in the art can therefore easily modify the path thereof for any other application which is considered of mn t nee- It should bepointed out that the invention has been illustrated and described solely by way of example and that various modifications and alterations can be made therein without departing from the scope thereof as defined by the appended claims.

What I claim is:

1. A safety and fire transmission device for projectiles provided with a fuze and a detonator spaced from said fuze, comprising a hollow body member adapted to be fixed in the projectile, the base of said body member havinga longi-, tudinal aperture opposite the detonator, an elongated rotatable obturator member journaled within said body and having a longitudinal pas sage with an eccentric portion, a resilient means i side the body memberie si anaxiauy uid member outside the body member, and supported by the resilient means, said axially guided member being adapted to be moved under the effect of the positive acceleration of the pro- J'ectile against the action of the said resilient means and effecting the rotation of said obturator member, one of said obturator member and axially guided member being formed with a groove the extremities of which are angularly displaced from each other about the axis of the device, a sliding element on the other said member, said sliding element being guided in said groove, said eccentric portion of the passage in the obturator member when the said member is rotated, being brought into registration with the inner end of the longitudinal aperture of said body member.

2. A safety and fire transmission device for self-propelled projectiles provided with a fuze and a detonator spaced from said fuze, comprising a hollow body member adapted to be fixed in the projectile, the base of said body member having a longitudinal aperture opposite the detonator, an elongated rotatable obturator member journaled Within said body and having a longitudinal passage with an eccentric portion, a resilient means outside the body member and an axially guided member outside the body member, and supported by the resilient means, said axially guided member being adapted to be moved under the efiect of the positive acceleration of the projectile against the action of the said resilient means and efiecting the rotation of said obturator member, one of said obturator member and axially guided member being formed with a groove the extremities of which are angularly displaced from each other about the axis of the device, said groove being formed by an initial sinuous portion, an intermediate helicoidal portion and a terminal blind portion, a sliding element on the other said member, said sliding element movable in said groove and being guided therein through the initial and intermediate portions during the positive acceleration of the projectile and being locked in the terminal blind portion when the self-propulsion ceases, said eccentric portion of the passage in the obturator member when the said member is rotated, being brought into registration with the inner end of the longitudinal aperture of said body member.

3. A safety and transmission device as defined in claim 2 including a retaining element which prevents axial displacement of the rotatable obturator member.

4. A safety and transmission device as defined in claim 2 wherein a longitudinal slot is out in the body member of the device to receive the said sliding element on the axially guided member.

EDGAR WILLIAM BRANDT.

References Cited in the file of this patent UNITED STATES PATENTS 

